Dr. Embury, a veterinarian, has recently completed residency training in Anatomic Pathology. The objective of her training was to gain expertise in characterizing genetically-engineered animals, with a goal of an academic position in basic research involving laboratory animals. Dr. Embury initially participated (1998-1999) in the construction and molecular characterization of AAV- based gene therapy vectors for the treatment of Phenylketonuria (PKU) in the Pahenu2 mouse model. This metabolic disorder is one of the most common human birth defects and results in severe CNS disturbances. After completing her residency, she returned on a full-time basis and is currently engaged in the pathological evaluation of Pahenu2 mice. She will continue this investigation, as well as increase her knowledge of neuropathology, in line with her career goals of a faculty position involved in the characterization of genetically engineered animal models. The immediate objectives of this proposal are to examine the neuropathogenesis of PKU in the Pahenu2 mouse model, both validating the results of gene therapy and providing preclinical data. The three Specific Aims are: 1) Characterize histopathologic lesions within the posterior periventricular hypothalamic nuclei and the mesencephalon in Pahenu2 mice; 2) Establish a time course of neuropathologic development in Pahenu2 neonatal mice; and 3) Evaluate the efficacy of gene therapy treatment on neurological deficits in Pahenu2 mice. This work will be conducted in the Department of Biochemistry and Molecular Biology and the McKnight Brain Institute, University of Florida College of Medicine. Dr. Laipis, the primary mentor, has phenotypically corrected PKU in the Pahenu2 mouse with AAV-based vectors, and will provide the host laboratory and necessary support for the research program. Additional faculty, experienced in neuropathology, neurodevelopment and rodent behavior have agreed to participate in Dr. Embury's training and experiments. We believe that the experimental plan presented in this proposal, combined with selected courses in neuroscience and research methods as well as continued participation in clinical case presentations in neuropathology can provide the specialized training needed for her development. In addition, she will have continued exposure to and participation in the molecular biological methods of biomedical research through her involvement in the Laipis laboratory.